1<HTML> 2<!-- 3 Copyright (c) Jeremy Siek, Lie-Quan Lee, and Andrew Lumsdaine 2000 4 5 Distributed under the Boost Software License, Version 1.0. 6 (See accompanying file LICENSE_1_0.txt or copy at 7 http://www.boost.org/LICENSE_1_0.txt) 8 --> 9<Head> 10<Title>Boost Graph Library: opposite</Title> 11<BODY BGCOLOR="#ffffff" LINK="#0000ee" TEXT="#000000" VLINK="#551a8b" 12 ALINK="#ff0000"> 13<IMG SRC="../../../boost.png" 14 ALT="C++ Boost" width="277" height="86"> 15 16<BR Clear> 17 18<H1><A NAME="sec:opposite"></A> 19<TT>opposite</TT> 20</H1> 21 22<P> 23<DIV ALIGN="left"> 24<TABLE CELLPADDING=3 border> 25 26<TR><TH ALIGN="LEFT"><B>Complexity:</B></TH> 27<TD ALIGN="LEFT"><i>O(1)</i> 28</TD> 29</TR> 30 31<TR><TH ALIGN="LEFT"><B>Where Defined:</B></TH> 32<TD ALIGN="LEFT"> 33<a href="../../../boost/graph/graph_utility.hpp"><TT>boost/graph/graph_utility.hpp</TT></a> 34</TD> 35 36</TABLE> 37</DIV> 38 39<P> 40<PRE> 41 template <class Graph> 42 typename graph_traits<Graph>::vertex_descriptor 43 opposite(typename graph_traits<Graph>::edge_descriptor e, 44 typename graph_traits<Graph>::vertex_descriptor v, 45 const Graph& g) 46</pre> 47 48Given an edge and a vertex which must be incident to the edge, this 49function returns the opposite vertex. So if <tt>v</tt> is the source 50vertex, this function returns the target vertex. If <tt>v</tt> is the 51target, then this function returns the source vertex. 52 53<h3>Example</h3> 54 55<pre> 56edge_descriptor e; 57... 58vertex_descriptor u, v; 59boost::tie(u, v) = incident(e, g); 60assert(v == opposite(e, u, g)); 61assert(u == opposite(e, v, g)); 62</pre> 63 64<br> 65<HR> 66<TABLE> 67<TR valign=top> 68<TD nowrap>Copyright © 2000-2001</TD><TD> 69<A HREF="http://www.boost.org/people/jeremy_siek.htm">Jeremy Siek</A>, 70Indiana University (<A 71HREF="mailto:jsiek@osl.iu.edu">jsiek@osl.iu.edu</A>)<br> 72<A HREF="http://www.boost.org/people/liequan_lee.htm">Lie-Quan Lee</A>, Indiana University (<A HREF="mailto:llee@cs.indiana.edu">llee@cs.indiana.edu</A>)<br> 73<A HREF="https://homes.cs.washington.edu/~al75">Andrew Lumsdaine</A>, 74Indiana University (<A 75HREF="mailto:lums@osl.iu.edu">lums@osl.iu.edu</A>) 76</TD></TR></TABLE> 77 78</BODY> 79</HTML> 80
